Iain Martin is a political commentator, and a former editor of The Scotsman and former deputy editor of The Sunday Telegraph. He is the author of Making It Happen: Fred Goodwin, RBS and the men who blew up the British economy, published by Simon & Schuster.. As well as this blog, he writes a column for The Sunday Telegraph. You can read more about Iain by visiting his website

Alex Salmond's plan to win the independence referendum by reassuring Scottish voters is in ruins

The pro-Union Better Together campaign undoubtedly took a risk when it decided to dynamite the SNP's currency union proposal last week. There is a danger that some undecided Scottish voters hear the warnings from George Osborne, Ed Balls, Danny Alexander and others that Scotland will not be able to keep the pound, with the Bank of England as lender of last resort for Scottish banks, and think: well, stuff you then and start supporting independence because they don't like the thought that they are being bossed around. The Nationalists are hoping that enough floating voters in the referendum respond to the UK parties by turning round and showing England a woad-painted backside.

This hope – and him not knowing what else to say, so astonished is he by the combined Unionist assault – probably explains why Alex Salmond keeps saying the same thing every single day in response. Day five, and the SNP leader is still at it. It is desperate stuff. It is becoming embarrassing.

Today Salmond is accusing the UK government of posturing, a variation on his theme of London bullying Scotland. In a speech to business leaders he is explaining why the UK should and will agree a currency union. But the UK parties and the Treasury explained last week why they won't. His response to this enormous setback seems to consist solely of calling those he seeks to negotiate with names (big bad blustering bullies) in the doomed hope that this will change their minds. He is trying a similar tactic with the President of the European Commission, who said yesterday that Scotland would not automatically become an EU member as Salmond claims, that a long period of negotiation would ensue and that it is difficult to envisage all member states agreeing to admit a nationalist Scotland (especially a new state opposed to joining the euro). The Nat response has been to call him a "preposterous" man. That'll win José Manuel Barroso round!

Despite concerns about the potential reaction from some voters, the risk on the currency had to be taken by Better Together. The UK parties aren't trying to boss Scottish voters; they are simply explaining the realities, politely, in good time ahead of the referendum. It would have looked tricksy to wait much longer, and those leading the campaign for a No vote in September know from polls and focus groups that undecided voters want answers, particularly on questions such as the pound. Their biggest concern is about economic uncertainty and the suspicion that Salmond might be winging it. The No campaign has just shown those voters definitively that the First Minister has based his referendum strategy on a string of lazy assertions.

The Nationalists – reduced to putting their fingers in their ears and shouting – are now in disarray. The currency is the bigger blow, but the combination of it with the EU row is dreadful for Yes, because the events of the last week undermined the very foundations of Salmond's campaign.

The SNP leader's great insight, which he worked out decades ago, was that a "cry freedom" approach would not deliver independence. Although there is a portion of the Scottish electorate, perhaps a quarter, perhaps a little more, that is nationalist to its boot straps, which is attracted by the emotional arguments for a separate state, it is never going to be enough. Salmond needed to convince other voters that it was safe to go for independence; that even though it felt like a big change, a great deal – the pound, the EU and the Queen – would stay the same.

So Salmond approached it step by step, rather brilliantly. He even won an overall majority in the Scottish parliament elections in 2011. As the father of the gradualist movement in the SNP, which held that the party should sign up to devolution and gradually convince Scotland to go for independence, he appeared to have been vindicated. When a referendum on independence materialised Salmond stood, in nationalist terms, on the verge of historical greatness.

Here he hit a snag. Years of skilfully executed guerrilla warfare against Scottish Labour, followed by the successes of governing Scotland, seem to have made Salmond and his team arrogant. They made an elementary mistake. They forgot that their opponents – Better Together in Scotland, Westminster and the UK parties – were capable of responding. They weren't going to fight this according to the script the nationalists had written. The rest of the UK and Scottish Unionists were always going to stick up for themselves and fight back against people out to destroy the United Kingdom. Which is exactly what they have done in recent weeks, to spectacular effect.

Salmond sensibly built his pitch in the referendum campaign around an attempt to offer reassurance, but he failed to either nail down the details in advance or find a credible way of explaining that all would not be plain sailing after a Yes vote. And now his offer – vote "Yes" and fear not, you will still keep the pound and Scotland remains in the EU – has been reduced to rubble.

Instead, the offer to undecided voters from the Yes campaign now involves a lot of shouting, no currency union, uncertainty about an alternative to the pound and several years of very difficult negotiations with the EU. This is a calamity for the nationalists, which leaves them only seven months from the referendum doing the opposite of what Salmond and his team had intended. They are falling back on the chippy politics of grievance when they needed to reach out and reassure.